Seven-year-old Selana Lee Clement sat quietly yesterday at the witness table of the Department of Transportation's hearing into safety-related problems with the Firestone 500 steel-belted radial tire.

She didn't say a word.

She had walked in on crutches, with the help of her father. Her mother and her aunt were killed in a June 24 auto crash in South Carolina that her attorneys say was caused by a defective Firestone 500 steel-belted radial. The tire blew out or fell apart and wrapped around the axle of the 1977 Chevrolet Monza, locking the wheels of the car, sending it out of control across a highway and into an oncoming vehicle, they said.

It was in the same accident that Selana, who was in the back seat, lost her right leg.

While Selana sat and listened, sometimes holding her father's hand, Rep. John Jenrette Jr. (D.S.C.), began the testimony at the hearings by pointing to the Clement family tragedy, which occurred long after public reports of problems with the Firestone 500 began appearing. Then he asked:

"Could this have been prevented by timely action by the manufacturer, or anyone else?"

He was followed by Clement family attorneys James T. Kalyvas and Neil Wright, who testified that, "it is our contention that the failure was due to defects present at the completion of the manufacture of the tire."

Recent news reports indicating that Firestone was selling large numbers of 500s (which were phased out of production last year) at discount prices in the South inspired the Clement family to come to the hearings, Kalyvas said. "Their hope is that by relating this incident they will prevent it from happening again and again across the land."

Last month DOT's National Highway Traffic Safety Administration made an "initial determination" that a safety related defect exist in the tire, and called on the company to recall the estimated 13 million 500's still on the road.

Firestone refused to recall the tires, and stated that the problems encountered usually were caused by the tires being inflated improperly.

But NHTSA cited "more than 6,000 reports from customers alleging more than 14,000 individual tire failure, 29 deaths, more than 50 injuries and hundred of property damage accidents."

The safety agency also said that the Firestone tire had the highest rate of adjustment of five major tire manufacturers surveyed. Adjustments (in which tires are exchanged after price allowances for wear) have involved about 1.5 million of the tires, which were also sold by Montgomery Ward (The "Grappler Radial") and Shell Oil Co. (The "Super Shell Steel Radial").

Hearings were set by NHTSA for yesterday and today to hear from Firestone on the issue of the possible recall which could cost the company an estimated $100 million. Yesterday's hearings were devoted primarily to victims of car accidents allegedly caused by defective Firestone tires.

But one witness was Paul Levy, first assistant Attorney General of New Jersey, which is considering the possibility of filing a class action suit for New Jersey tire owners against Firestone.

Levy said his office set up a special tire hotline and asked New Jersey consumers who had problems with the 500 to call.

"The response was overwhelming," he said. "Caller after caller described blowouts and such defects as splits and cracks, bubbles and blisters on sidewalls, tread separation, uneven wear, protusion of steel belt wire and out of round condition."

Levy said he knew of cases where Firestone dealers replaced reportedly defective 500's with other 500's. Bother Levy, and New Jersey consumer affairs official Adam Levin said the tires involved in most of the complaints they received were defective.

"It is clear," said Levin, "that the present situation is intolerable . . . the only remedy that can fully and fairly satisfy consumers who have had "500" problems is a recall."

Firestone officials are scheduled to testify today. But Firestone Public Relations director Bernard Frazier, who attended yesterday's session, said his company "is concerned about any accidents, especially ones that result in fatalities or injuries. There are serious and often tragic circumstances."

But Frazier said that "accidents and causes of accidents require careful examination. Making charges is not the same as stating facts in a case he added.

"What we have been hearing about today," Frazier said, are separate incidents with a variety of causes under widely varying and particular circumstances. To bring people together in the same room on the same day does not mean their accidents have a common cause.

"The cause of an accident must be determined scientifically and not emotionally," he said.

At today's hearing, Firestone's attorneys are expected to maintain that the radical 500 was comparable to the first generation of steel belted radial tires of other manufacturers.

Sources say the Firestone lawyers will also contend that NHTSA, in order to make a finding that a defect exists, should base such a finding on comparative scientific evaluation of that tire with others and not on "incidents that are really not subject to reliable analysis."